A new type of warfare, named terrorism, pervades the world. Civilized nations lie at the mercy of fanatics and guerrillas who are willing to blow themselves to bits in order to destroy an embassy, a troop barracks, or a skyscraper office building. Their most insidious weapon thus far is the so-called "car bomb", i.e., an explosive laden vehicle which is driven through a check point or into a barricaded security station so as to get close enough to a building to blow it up, even though the building itself is not breached.
Barricades across a roadway are only partly effective because, in most instances, the roadway must be used to transport goods or personnel to and from a secured area, and if a removable barricade is relied upon, it must have enough mass to withstand the onslaught of a powerful fast-moving vehicle. This very mass, which requires force to move it so as to clear or block a roadway, renders its actions slow and generally requires external power to move it, and a clever intruder may disable the power supply at the very moment it is needed to install the barricade. Draconian measures are needed.